1. Field of the Invention
The present invention relates, in general, to electrical power service to homes and buildings and, more specifically, to watthour meters, meter sockets and watthour meter socket adapters.
2. Description of the Art
Electrical power is supplied to an individual site or service by electrical power line conductors located above or below ground. In a conventional arrangement, electrical power line conductors are connected to contacts in a watthour meter socket mounted on a building wall. Electrical load conductors are connected to another set of contacts in the meter socket and extend to the electrical distribution network in the building. A watthour meter, typically of the plug-in, socket type, is connected to the contacts in the meter socket to measure the electrical power drawn through the load conductors.
Plug-in watthour meter socket adapters and socket adapters/extenders, both hereafter referred to simply as socket adapters, are designed to plug into the meter socket housing contacts. Such socket adapters are employed to convert ringless style sockets to ring style sockets or to extend the mounting position of the jaw terminals in the socket housing outward from the socket housing for mounting various electrical equipment, such as test devices or survey recorders, in the socket housing.
Such socket adapters employ a generally annular base having a shell joined thereto and extending outward from one side of the base. Contacts are mounted in the shell and base. Each contact has a female jaw portion disposed interiorly within the shell and a male blade terminal connected to the female jaw portion and extending outward from the shell and the base for a plug-in connection to the terminals in the meter socket housing.
While it is typical for a watthour meter, once it is installed in a socket or socket and socket adapter, to remain in service for many years, it is still necessary for such meters to be removed for repair or replacement from time to time as well as to temporarily disconnect electrical service to a particular customer. During the installation and removal of the watthour meter from the socket or socket adapter, the electric power line terminals in the socket or socket adapter remain connected to the electric utility power line conductors and carry potential. The utility employee installing or removing the watthour meter may inadvertently touch such contacts thereby raising the possibility of injury. Furthermore, an inadvertent short across the contacts caused by a tool contacting the contacts or a full fault caused by a 90xc2x0 offset insertion of the meter can cause a spark or flash which could damage the watthour meter installation as well as posing a significant risk of injury to the utility employee.
In U.S. Pat. No. 5,577,933, a unique safety shield for a watthour meter mounting apparatus is disclosed which completely covers all of the exposed portions of the jaw contacts to prevent inadvertent contact with such contacts by the utility employee or by a tool.
One embodiment of this safety shield is in the form of a housing having a unitary sidewall and top wall defining a closed body with an internal recess surrounding the jaw contacts. Narrow apertures or slots are formed in the top wall for receiving the blade terminals of a watthour meter therethrough into engagement with jaw contacts disposed immediately below each aperture in the top wall of the safety shield. In another embodiment, a plurality of receptacles extend from a planar wall mountable in the socket adapter, with each receptacle having one or more slots for receiving the meter blade terminals therethrough. The individual receptacles are sized to completely surround at least one jaw contact in the socket adapter.
Improved versions of Applicants"" safety shield as shown in U.S. Pat. Nos. 5,572,386, 5,577,933 and 6,325,666. These safety shields have been designed for a snap-in connection to the socket adapter base by means of legs having clip end portions which snap through apertures formed in the base wall of the socket adapter housing.
In certain electrical service apparatus or electric watthour meter socket adapter applications, the status or state of certain devices mounted interiorly within the housing of the socket adapter, such as the conductive or non-conductive state of surge suppression devices, such as MOVs, must be communicated exteriorly of the socket adapter housing to enable a service person to easily determine the operative or inoperative state of such devices without removing the watthour meter from the socket adapter.
Previously, wires from signal generating devices on circuit boards within the meter or adapter housing were connected to light bulbs mounted in the sidewall of the housing. This, however, has increased labor and added additional components to the meter or socket adapter. The wire, if broken, also resents an electrical hazard to anyone coming in contact with the wire or when the wire is wet.
It is also known in watthour meters to provide an optocoupler on the face or dome of the meter to enable a light generating programmer to be coupled to the exterior end of the optocoupler for communicating optical data signals to and from meter electronics. In this structure, the optocoupler represents a separate device which is physically mounted on the dome of the meter for optical communication through the dome.
It would be desirable to provide an electrical power service apparatus which has a light transmissive guide for establishing an optical communication path between interior mounted components and the exterior of the electrical power service apparatus which can be easily and economically mounted in the housing of the electrical power service apparatus without the need for additional wiring.
The present invention is an improved electrical service apparatus with a light transmission guide.
In one aspect of the invention, the light transmissive means or guide is mounted on or attached to a jaw contact safety shield. This enables integral mounting of the light transmissive guide in the desired position in the electrical service apparatus at the same time as the safety shield is mounted in the apparatus.
In one aspect, the light transmissive means or guide has first and second ends, the first end adapted to be disposed in proximity with a light generating source and/or light receptive element within the socket adapter to transmit light generated by the light generating source to the second end of the light guide or from the second end to the first end. Preferably, the second end of the light transmissive means is disposed through or visible through an aperture in the sidewall of the socket adapter housing for external access.
In another aspect, the light transmissive guide is formed as a separate element which is usable separately or in combination with a jaw contact safety shield, or mounted in the electrical service apparatus separate from any optional safety shield from the optional safety shield. For example, one or more inlet ends of a light transmissive means or guide, each disposed in light coupling arrangement with a separate light source are operative to transmit light from the respective light source to a common outlet which is visible exteriorly of the housing of the electrical service apparatus. In this aspect, the outlet end of the light transmissive means or guide is fixedly mounted in an aperture formed in a sidewall of the housing of the electrical service apparatus. The reverse direction of light transmission from the outlet end to one or both of the first inlets.
The present invention adds new functionality to electrical service apparatus. The unique light transmissive means or guide of the present invention uniquely enables light generated by a light generating source, such as an LED, in a functional circuit mountable within the socket adapter, to be transmitted to a more easily visible position, such as externally of the socket adapter. This enables the function indicated by the light generating source to be easily detected exteriorly of the socket adapter without requiring removal of the socket adapter from the watthour meter socket. At the same time, light from an external light source can be transmitted through the light guide to a light receptive element within the housing.